1. Field of the Invention
The present invention relates to a test tube cap removing apparatus for automatically removing a cap that is attached to an opening portion of a test tube in which a specimen is to be contained.
2. Description of the Related Art
In a conventional test tube cap removing apparatus, a cap that closes the opening of a test tube is clamped by distal end portions of cap-removing arms in the state in which the test tube is clamped by a test tube clamper. In this apparatus, the cap-removing arms are pulled up by a cap-removing-arm drive cylinder, thereby automatically removing the cap.
Document 1 (Jpn. Pat. Appln. KOKAI Publication No. 5-228379) discloses a test tube cap removing apparatus wherein grippers are provided on the distal end portions of cap-removing arms. When the cap-removing arms are pulled up by a drive cylinder, the cap is rotated about its axis in association with inclining guides.
Test tubes, which are specimen containers, come in various sizes. For example, the relationship of “diameter×length” of the tube may be: φ13 mm×75 mm, φ13 mm×100 mm, φ16 mm×75 mm, or φ16 mm×100 mm. A specimen, such as blood, is contained in the test tube.
There are various types of caps for closing openings of test tubes, which include, for instance, a push-in type rubber cap, a cork cap, a screw cap, and a cap of a Sarstedt tube.
The test tube cap removing apparatus according to Document 1 is applicable to a case where a cap of a standard type, which is applied to a test tube of a fixed size, is to be removed.
However, with the test tube cap removing apparatus of Document 1, if the size of the test tube or the type of the cap is changed, it is difficult to remove the test tube cap.
In Document 1, the cap-removing arms of the test tube cap removing apparatus are provided with a mechanism for rotating the cap about its axis in association with the inclining guides when the cap is to be removed.
This rotating mechanism, however, is a mechanism that is designed mainly to reduce the force which is needed to remove the cap. This mechanism does not function to stably remove, e.g. a screw cap by rotating the screw cap with a necessary amount of rotation.
In short, Document 1 is silent on an adjusting mechanism for making the cap removing apparatus usable even when the size of the test tube or the type of the cap is changed. Such an adjusting mechanism is, for example, a mechanism for adjusting the positional relationship between a test tube clamper and a cap-removing arm, or a mechanism for removing a screw cap.